Minimally Invasive Zadek Osteotomy vs Open Achilles Debridement for Insertional Achilles Tendinopathy in Athletes: A Retrospective Comparative Cohort Study

Background: Insertional Achilles tendinopathy (IAT) is a common cause of posterior heel pain in athletic populations and may require surgical intervention following failed conservative management. Minimally invasive Zadek osteotomy (MIS Zadek) has emerged as an alternative to traditional open Achilles tendon debridement with Haglund resection, with potential advantages in recovery and complication profile. Methods: A retrospective comparative cohort study was performed including 50 athletic patients with IAT (25 MIS Zadek, 25 open surgery) treated between 2022 and 2024 at a single high-volume centre. All patients participated in regular sports activity and failed at least 6 months of nonoperative treatment. The primary outcome was time to return to sport. Secondary outcomes included return-to-sport rate, Patient-Reported Outcomes Measurement Information System (PROMIS) physical function (PF), PROMIS pain interference (PI), and postoperative complications. Multivariable regression analysis was performed to adjust for potential confounders. Results: Return to sport was achieved in 100% of MIS patients (25/25) and 92% of open patients (23/25; P = .49). Time to return to sport was shorter following MIS Zadek (4.3 ± 1.2 vs 6.1 ± 1.5 months; mean difference −1.8 months, 95% CI −2.6 to −1.0; P < .001). MIS remained independently associated with faster return to sport (adjusted β = −1.6 months, 95% CI −2.4 to −0.8; P < .001). Both groups showed substantial and clinically meaningful improvements in PROMIS outcomes. At 6 months, PROMIS PF was higher in the MIS group (56.5 ± 5.8 vs 52.3 ± 6.4; mean difference +4.2, 95% CI 0.6-7.8; P = .02; Cohen d = 0.69), with a similar pattern for PROMIS PI (47.2 ± 5.5 vs 51.1 ± 6.0; mean difference −3.9, 95% CI −7.1 to −0.7; P = .02; Cohen d = 0.67). By 18 months, PROMIS PF improved further in both groups with comparable outcomes (59.4 ± 4.9 vs 57.8 ± 5.2; mean difference +1.6, 95% CI −1.4 to 4.6; P = .29), and PROMIS PI similarly converged (44.8 ± 4.9 vs 46.3 ± 5.1; mean difference –1.5, 95% CI −4.4 to 1.4; P = .30). Complication rates were lower in the MIS group (2/25, 8%) compared with the open group (6/25, 24%; P = .25), although this difference did not reach statistical significance. Conclusion: MIS Zadek osteotomy was associated with faster return to sport and improved early recovery compared with open surgery; with the numbers available, no significant difference in long-term functional outcomes could be detected. Complications were numerically less frequent following MIS Zadek osteotomy, although this difference did not reach statistical significance Level of Evidence: Level III, retrospective comparative cohort study.